Method of lubricating anti-friction bearings with bonded film lubricants



April ll, 1961 E. R

METHOD 0F LUBRICA WITH BON Original F11@ WQ L@ W d M M Unite States Sewell, NJ., and Martin J. Devine, 2560 Prescott Road, Havertown, Pa.

Original application Apr. 16, 1958, Ser. No. 729,039. l7)ivided and this application Oct. 27, 1958, Ser. No.

20 Claims. (Cl. 29-148.4)

(Granted under Title 3'5, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This application is a divisional application of co-pending application Serial No. 729,039, filed April 16, 1958.

The invention relates to anti-friction bearings with bonded film lubrication and Ito a method of lubricating anti-friction bearings with bonded film lubricants. More particularly, the invention relates to high speed and high temperature anti-friction bearings such as ball bearings having solid or dry-type lubricants affixed or bonded to the components thereof and to a method of lubricating high speed and high temperature anti-friction bearings by alixing dry-type lubricants to the unassembled components of the bearings.

Prior attempts to lubricate high speed and high temperature anti-,friction bearings with both wet-type lubricants such as greases and bonded film lubricants utilizing a dry-type lubricant or lubricants have been universally unsuccessful. It is well known that grease-type lubricants provide excellent lubrication for anti-friction bearings operated under conditions :of relatively low speed and low temperature but have several inherent disadvantages when the bearings are operated under other conditions. For example, at high temperatures, greases become less viscous and have a tendency to seep or leak from a bearing, this loss due to seepage or leakage eventually and many times very quickly resulting in a failure of the greases to provide a film of lubricant between the friction lor coacting surfaces ofthe bearing components. Conversely, at low temperatures, greases substantially increase in viscosity and materially add to the frictional drag or operating torque of a bearing. When geases are used at high temperatures coupled with a high vacuum, the `greases vaporize and evaporate and thus deprive the bearing of the needed lubrication. It is also well known that greases deteriorate rapidly when exposed to certain types of chemical attack and nuclear radiation.

Bonded film lubricants, on the other hand, utilizing a dry-type lubricant such as a mixture of graphite and molybdenum disulphide as the lubricating constituent of the bonded film, possess none of the inherent disadvantages of the wet-type lubricants, but, nevertheless, have never heretofore been successfully employed as a lubricating medium for `high speed and high temperature antifrictionI bearings. This failure to successfully lubricate bearings of this type with bondedfilm lubrication has resulted primarily from the failure to develop a method or technique whereby a bonded film lubricant having a substantially uniform predetermined thickness could be af" fixed to either all of the components 'of an anti-friction bearing, selected components of an anti-friction bearing, or selected surface of selected components of an anti-friction bearing. A bonded film of substantially uniform .ice

thickness s extremely important in the lubrication of high speed and high temperature anti-friction bearings due to the critical tolerances between the friction surfaces of the bearing components. A bonded filrn which is not substantially uniform in thickness will interfere with the proper relative movement between the components of the bearing and thus produce undesirable fri-ctional forces and heat which will result in a cracking or failure of the bonded film. Bonding or afxing a lubricant to selected components only or to selected surfaces of selected components of an anti-friction bearing is also an important factor in the successful utilization of bonded film lubricants from the standpoint of the use or the environmental application of the bearing. In many environment applications, it has been found desirable and advantageous not to affix a lubricant to all of the components or to all of the surfaces of the components of an anti-friction bearing.

Accordingly, one of the objects of the present invention is to lubricate an anti-friction bearing with a bonded film lubricant.

Another :object of the invention is to provide an antifriction bearing with a bonded film lubricant of substantially uniform thickness on the components of the bearing.

Another object of the invention is to provide an antifriction bearing with a bonded lm lubricant of substantially uniform thickness on selected components or on selected surfaces of selected components of the bearing.

Another object of the invention is to provide a lubricated anti-friction bearing having a substantially uniform operating torque over the entire operating temperature range of the lubricant.

Another object of the invention is to provide a method of lubricating an anti-friction bearing with a bonded film lubricant having a substantially uniform thickness.

Another object of the invention is to provide a method of lubricating an anti-friction bearing wherein selected components only of the bearing are lubricated with a bonded film lubricant having a substantially uniform thickness. t

Another object of the invention is to provide a method of lubricating an anti-friction bearing wherein only selected surfaces of selected components of the bearing are lubricated with a bonded film lubricant having a substantially uniform thickness.

In conformity with these objects, the preferred embodiment of the invention is characterized by a high speed and l high tempera-ture ball bearing having a comminuted drytype lubricant bonded or aixed to all of the components thereof by a bonding agent comprised of a hardened thermosetting resin. The comminuted lubricant. is uniformly dispersed in the bonding agent and the bearing components are completely surrounded or enveloped by a lubrieating lm having a substantially uniform thickness. The

preferred method envisioned by the invention for lubricating an anti-friction bearing such as a high speed and high temperature ball bearing includes the steps of coating all of the components of the bearing in an unassembled state with a dry-type or solid comminuted lubricant suspended in a thermosetting bonding agent, heating the coated components to harden the bonding agent, and then reassembling the lubricated components into an operative unit to provide an anti-friction bearing having a bonded film lubricant on the friction surfaces thereof. The coating must, of necessity, be applied in a manner to provide a lubricating film of substantially uniform thickness, and

the selection of the exact constituents for the coating mix# ture will be determined mainly by the conditions under which the bearing is expected to operate or perform.

These and other objects of the present invention will become readily apparent from the following description 3 taken in connection with the accompanying drawings, wherein:

Fig. l is a side elevation of a ball bearing illustrating a preferred embodiment of the invention;

Fig. 2 is an enlarged section taken along the line II--ll of Fig'. l; Y i

Fig. 3 is a side elevation of a ball bearing illustrating ano-ther embodiment of the invention; t

Fig. 4 is an enlarged section taken along the line IVfiV of Fig. 3;

Fig. 5 is a side elevation of a ball bearing illustrating another embodiment of the invention; and

Fig. 6 is an enlarged section taken along line VI-VI of Fig. 5.

Referring more particularly to the drawings wherein like structural details and components are designated by likereference numerals, Figures l and 2 show an antifriction bearing 8 of the ball-type having components including anI inner ring or race means l0 provided with a circumferentially extending groove or raceway 12 in the outer periphery i4 thereof and an outer ring or race means lid provided with a eircumferentially extending groove or raceway l in the inner periphery thereof. A plurality of substantially spherical rolling elements or balls 22, in this instance ten in number, are carried in the raceways l2 and 1S and, due to a predetermined curvature of the raceways 12 and 18, are confined therein for rotary movement in asubstantially circular orbit between the inner and outer race means 10 and 16, respectively. Being substantially spherical, balls 22 are also capable of independent rotary movement about their own geometrical axes and thus are capable of rotation both relative to themselves and to the inner and outer race means 10 and i6. A predetermined clearance or tolerance (not shown in the drawings) between the balls 22 and the Vraceways l2 and 18 permits the balls 22 to roll freely over the surfaces of the raceways.

-A separator or cage means 24` is carried by the balls 22 and serves to space the balls 22 a uniform or equal distance apart in order to equalize any load that may be applied to the balls 22. through the races 10 and 16. The cage means 24 is provided with a plurality, in 'this instance ten, of pockets or the like 26 therein (Fig. l) each of which (Fig. 2) is adapted to receive a ball 22. The inner periphery of each pocket 26 is provided with a predetermined curvature and is adapted to be carried on and thus frictionally engage the peripheral surface of its received ball 22.

The components of the anti-friction bearing 8 in this preferred embodiment of the invention are made of steel but may be made of any other material suitable for bearing use such as iron, stainless steel, etc. Various alloys of steel and stainless steel have been found to be particularly satisfactory materials for use in the construction of high speed and high temperature anti-friction bearings. inasmuch as the structure and function of balltype anti-friction bearings as well as the materials utilized in the construction thereof are well known in the art and per se form no part of the present invention, further discussion thereof is deemed unnecessary. Sufiice it to say that in the use or environment application of the bearing 8, the inner race means 10 is adapted to receive a shaft or the like (not shown) which when rotated will also rotate the inner race means 10 and thereby impart rotation to the balls 22.

As best seen in Fig. 2, all of the components 10, 16, 22 and 24 of the bearing S carry a lubricating film or coating 28 which completely surrounds or envelops each of the components. The film lubricant 28 is tightly afxed or bonded to the components and constituentwise is comprised of a solid comminuted lubricant uniformly dispersed in a cured thermosetting bonding agent. In this preferred embodiment of the invention, the bonded film 28 is comprised of a mixture of iinely pulverized molybdenum disulphide and graphite dispersed in a cured phenolic resin, the pulverized lubricant being mixed in a substantially 9 :1 ratio by weight with 9 parts of molybdenum disulphide to l part of graphite. While the constituents utilized in this preferred embodiment have been found to provide satisfactory lubricating film, it will be appreciated of course that these constituents are merely illustrative of the invention and are not to be construed in a limiting sense. The selection of the particular constituents comprising the bonded film is strictly a matter of choice and may include any other suitable dry-type comminuted lubricant such as boron nitride, tungsten disulphide or the like in combination with other suitable thermosetting bonding agents such as formaldehyde resins, silicone resins and vinyl resins. ,Sufce it to say, however, that the thermosetting agent selected should be capable of forming a tight bond that does not crack or flake-off in use and should be resistant to the deleterious effects of heat and pressure and to the action of hydrocarbons such as greases, oils and the like.

The mixture of comminuted molybdenum disulphide and graphite utilized as the lubricant in the preferred embodiment of the invention is a 5 micron grade although the size of the graphite particles is not critical. It has been found, however, that a solid comminuted lubricant having a particle size not greater than 7 microns provides a better lubricating action than a lubricant of larger particle size. The smaller size lubricant particles have a tendency to become more evenly dispersed in theV mixed in equal or dissimilar proportions and the particleV size of the lubricants may also be varied. The selection of a single comminuted lubricant or a predetermined blend of two or more will, of course, be a matter of choice which will for the most part depend on the environmental application of the lubricated bearing. For example, if it is desired to operate an anti-friction bearing at an extremely high temperature, it has been found that a comminuted lubricant comprised wholly or principally of molybdenum disulphide or boron nitride will provide a much more satisfactory lubricant than graphite.

The film thickness of a bonded film lubricant is especially important from the standpoint of satisfactory bearing operation, and i-n the preferred embodiment of the invention (as best seen in Figure 2), film 2S on all of the components of bearing 8 has a thickness of approximately 0.0003. A film thickness of approximately 0.0003 is preferable in most instances although it should be pointed out that the film thickness per se is not critical. It has been found, however, through extensive use and experimentation, that a bonded film thickness of at least 0.0002 and not more than 0.0005 will provide the most satisfactory lubrication for anti-friction bearings.

late the bearing. The tolerances between the bearing components, the bearing speed and temperature, the temperature of the ambient atmosphere or cooling medium and the loading of the bearing are all factors which must be considered in making a selection of the proper thickness for the bonded film lubricant. Y

uns..

Although'it is preferable that the bonded film on all of the bearing components should be substantially identical in thickness and should be maintained within the 0.0002"0.0005" range, it will be apparent to thoseskilled in the art that the thickness of the bonded film may also be varied within the preferable range of 0.0002-0.0005" from one bearing component to another without affecting the optimum lubricating action or performance of the bonded film. For example, the bonded film on the balls of the bearing may have a thickness of 0.0002", on the race means may have a thickness of 0.0003 and on the cage means may have a thickness of 0.0005". On the other hand, it has also been found that the thickness of the bonded film on the cage means of a bearing may exceed and even greatly exceed the preferred maximum thickness of 0.0005" without seriously impairing the lubricating action of the bonded film. Bonded film thicknesses of up to 0.0012 have been found in some instances to provide satisfactory lubrication on a bearing cage means. This increase in film thickness on the cage means of a 'bearing over and above the thickness of the film on the other components of the bearing is permissible in view of the fact the tolerances between the cage means and the balls is not as closeas the tolerances between the other components of the bearing.l

It will also be noted in Fig. 2 that the bonded film 28 is substantially uniform in overall thickness on the surface or surfaces of each of the bearing components. This substantial uniformity in thickness is especially important from the stand-point of preventing rupture or failure of the bonded film, particularly when the bearing is operated at high speeds and high temperatures. Due to the critical tolerances between the surfaces of the components of an anti-friction bearing, a bonded lm which is not substantially uniform in thickness will readily produce undesirable frictional forces and heat which will quickly result in a failure of the bonded film.

Anti-friction bearings lubricated in accordance with the preferred embodiment of this invention and operated at shaft speeds of 10,000 r.p.m. and faster with light radial and thrust loads applied to the bearings have been found to perform satisfactorily for many hours without a failure or breakdown of the bonded film lubricant. On the other hand, it has also been found that when the balls or rolling elements of an anti-friction bearing in addition to the other components thereof are lubricated with a bonded film, the bearing will operate for much longer periods of time without failure ofthe bonded film if the shaft speed is kept below 10,000 r.p.m. and if the loading on the bearing is maintained at a relatively low value.

Figs. 3 and 4 show another embodiment of the invention wherein all of the components of an anti-friction bearing 30 except the balls 22 thereof are coated with a bonded film lubricant 28. Bearing 30 is otherwise identical in all structural `details to bearing 8 shown in Figures l `and 2, and the thickness of the bonded lm 28 within the limits hereinbefore discussed in connection with the preferred embodiment of the invention as well as the constituent mixture of the bonded film 28 is strictly a .i

matter of choice which is again dependent on the environmental application of bearing 30 and the conditions under which it is expected to operate. Performance tests have indicated that au anti-friction bearing lubricated in accordance with this embodiment of the invention will operate satisfactorily for many hours at shaft speeds of 10,000 r.p.m. with relatively heavy radial and axial loads applied to the bearing without failure ofthe bounded film 28. In general, it has been found that an anti-friction bearing lubricated as shown in Figs. 3 and 4 will operate satisfactorily for much longer periods of time and at higher speeds and under much heavier loading than an antifriction bearing lubricated in accordance with the preferred embodiment of the invention.

` 'Figs 5 and 6 show another embodiment of the inventonwherein an anti-friction bearing 32 is provided with a bonded film lubricant on only the cage means 24 and the raceways 12 and 18 thereof. Bearing 32 is otherwise identical in all structural details to bearing 30 ofFigs. 3 and 4. Bearing 32 has generally been found to have performance characteristics substantially identical to the performance characteristics of bearing 30,; however, its chief advantage over bearing 30 has been found to reside in certain environmental applications of the bearing wherein the widths ofthe bearing race means 10 and 16 and the outside diameter of the outer race means 16 are critical. By eliminating the bonded film lubricant on the two race means other than coating the surface of the raceways 12 and 18 thereof, the maximum outside dimensions of the two race means can be somewhat reduced.

Anti-friction bearings lubricated in accordance with the present invention have been found to perform satisfactorily and to possess a relatively low and a substantially uniform operating torque or frictional drag over a wide range of operating temperatures. Tests have shown that an anti-friction bearing lubricated in accordance with the preferred embodiment of the invention will perform at a susbtantially constant operating torque at temperatures ranging from -94 F. to 350 F. These tests also showed that there was very little difference between the starting and running torque of the bearing so lubricated. Tests `conducted on anti-friction bearings lubricated as shown in Figs. 3 and 4 and Figs. 5 and 6 also revealed the existence of a relatively low and substantially constant operating torque over a wide temperaure range, the temperature varying between -94 F. to 350 F.

Method i The preferred method of lubricating anti-friction bearings and more particularly high speed and high temperature ball-type bearings is comprised of the following steps, the method being operable to produce a lubricated bearing substantially identical to the lubricated anti-friction bearing shown in Figures 1 `and 2. The components of an unassembled ball bearing, the inner and outer race means, the balls or rolling elements and the cage means, are first cleaned to effect the removal of any contaminating foreign matter from the external surfaces thereof, particularly the removal of oils and greases. The cornponents are cleaned in this preferred embodiment by vapor degreasing with a trichloroethylene vapor, although it will be apparent that the components could be cleaned with any other suitable type of cleaning agent or could be cleaned in any other suitable manner. On the other hand, the cleaning step can be completely eliminated if the components are free of contaminating foreign matter. The cleaning step is merely an optional step to be used when necessary.

'The unassembled components of the bearing are then coated with a lubricating composition or film comprised of a solid comminuted lubricant suspended in a thermosetting bonding agent, which in this preferred embodiment is comprised of a mixture of finely pulverized or comminuted molybdenum disulphide and graphite suspended in a phenolic resin. The mixture of pulverized lubricants and phenolic resin is thinned by the addition of an organic solvent mixture thereto, Which in this preferred embodiment is comprised of a mixture of 50% methylethylketone, 25% xylene and 25% butanol, and the thinned mixture is then applied to the bearing components by spraying. The mixture may be thinned to any desired consistency suitable for spraying, and it will be appreciated that any suitable thinner other than the mixture used in connection with the preferred embodiment may be utilized, thinners Vsuch as xylene, xylene-toluene, toluene, etc.

The proportionate mixture of the constituents of the coating composition utilized in the preferred embodiment of the invention includes the following constituents in percentages by weight: molybdenum disulphide 18, graphite 2, phenolic resin 12, thinner `68. The proportionate mixture of constituents is not critical, however,` and will be determined mainly by such factors as the environmental application of the bearing and the tolerances between the components thereof. Furthermore, it will be readily understood by those skilled in the art that the percentages of Vthe constituents utilized in the preferred embodiment of the method is merely illustrative of the invention and is not to be interpreted in a limiting sense. Mixing of the constituents may be affected by any suitable means such as milling or agitating. The size of the graphite particles, likewise, is not critical although it has been found that solid lubricants having a particle size not greater than 7 microns provide the best lubrication. Accordingly, the comminuted graphite utilized in the preferred embodiment is of a 3 micron particle size.

A thermosetting bonding agent other than a phenolic resin may also be used. Organic bonding agents such as vsilicone resins, vinyl resins, and epoxy resins have been found to be satisfactory. As discussed hereinbefore, however, the bonding agent selected must be capable of holding a solid comminuted lubricant in suspension and must also be resistant to heat and pressure in addition to the attacks of various hydrocarbons.

Instead of a mixture of molybdenum disulphide and graphite, the lubricant in the coating composition may be comprised of only a single comminuted lubricant or a Vmixture of more than two comminuted lubricants. Other suitable lubricants in comminuted form such as boron nitride and tungsten disulphide may be utilized. The selection of a particular lubricant or lubricants is again, as discussed hereinbefore in connection with the preferred embodiment of the lubricated bearing (Figs. 1 and Z), a. matter of choice depending mainly on the environmental application of the bearing.

As also mentioned hereinbefore in connection with the preferred embodimentof the lubricated bearing, the coating composition on the bearing components must be substantially uniform in thickness and the thickness preferably should not be' less than 0.0002." or greater than 0.0005. Therefore, in spraying the components of the bearing, care must be exercised to insure the application of a substantially uniform film to` the components, the lrn `having in this preferred embodiment a thickness of approximately 0.0003. lt is also noteworthy to mention that it is preferable to rotate the bearing components while the lubricant coating is being sprayed thereon. The rotation of the components will facilitate the application of the coating to the components and will more or less insure that the coating will be substantially uniform in thickness on all of the surfaces of the components.

Although spraying is the preferred method by which the coating film is applied tothe bearing components, this invention also contemplates the use of any other suitable method of coating the components such as by dipping or brushing. Any suitable method may be utilized, but the method selected should insure the application of a substantially uniform film having a predetermined thickness.

After coating, the unassembled bearing components are air dried or dried at room temperature for a predetermined period. In the preferred embodiment of the invention, the coated components are air dried for one hour at an ambient temperature of 70 `F. lt will be understood of course that this preferred time and temperature are not critical and'may be varied to a considerable extent far above or far below these preferred values. The purpose of the air drying step is to insure the formation of a smooth external surface on the coating or iilm covering the bearing components through the slow evaporation of the solvent in the coating. On the other hand, when the coating includes a solvent having a high vapor pressure, the air drying step in the method may be omitted inasmuch as most of the solvent will have already evaporated Yupon completion of the spraying operation.

After air drying, the unassembled componentsY of the bearing are heatedto harden the thermosetting bonding agent Vand thereby tightly bond or afx the comminuted lubricant tothe bearing components. The coated components in the preferred embodiment are heated by baking, the components being baked for a period of one hour. at a temperature of 300 F. The temperature selected for heating obviously should not exceed the decomposition temperature of the coating but otherwiseV isnot critical. Any heating temperature which produces a quick thermosetting of the bonding agent and a consequent rigid bonding of the comminuted lubricant to the surfaces of the bearing components will be satisfactory.

After being heated, the unassembled components of` the bearing are -assembled into an operative unit to provide an anti-friction bearing substantially identical to the bearing shown in Figs. l and 2. having a bonded lubricant on all of the surfaces of the components thereof and, more particularly, on the friction surfaces of the components.

Another embodiment of this invention contemplates a method wherein all of the components of an anti-friction bearing except the rolling elements or balls thereof are coated with a bonded lubricant. In other words, this method is identical with the preferred method of lubricating an anti-friction bearing with the exception that the balls are not included in the cleaning, coating, air drying and heating steps of the process. An anti-'friction bearing lubricated in accordance with this embodiment of the invention would be substantially identical in structure. to the anti-friction bearing shown in Figs. 3 and 4.

Anothervembodiment of the present invention envisions the idea'of lubricating an anti-friction bearing by coating only the cage means and the raceways in the inner and outer race means with a bonded lm lubricant. In this embodiment of the invention, the inner and outer races of the bearing are masked after being cleaned to cover Vall of the external surfaces thereof other than the 'raceways therein. After the masking step, the cage means and the raceways only are coated with the lubricating composition. Aside from the masking step, this embodiment of the method is otherwise identical to the last embodiment and would result in the production of a lubricated bearing substantially identical in structure to the bearing shown in Figs. 5 and 6. Y

Although the present invention has been specifically shown and herein described in connection with a balltype antifriction bearing, it will readily be appreciated that the invention could be applied with equal facility to the lubrication of other types of anti-friction bearings such as-roller-type bearings.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specically described,

What is claimed is:

V1. A method of lubricating an anti-friction bearing comprising coating the unassembled components of the bearing with a comminuted solid lubricant suspended in a thermosetting composition, heating the coated unassembled components to harden the thermosetting composition and thereby tightly bond the comminuted lubricant to the unassembled components, and assembling the componentsV of said bearing into an operative unit to thereby provide an anti-friction bearing having a solid lubricant bonded on the coacting surfaces ofy the components thereof.

2. A method of lubricating a high speed and high tempeature anti-friction bearing having components including inner race means,voute'r race means, rolling elements associated with said Vinner and outer race means, and retainer means, comprising the steps of coating the unassembled components of said bearing with a comminuted solid lubricant suspended in an organic thermosetting resin, heating said coated unassembled components of said bearing for a predetermined time at a predetermined' agr/agree` temperature to harden said thermosetting resin and thereby bond said solid lubricant to said components of said bearing, and assembling said components into an operative unit to thereby provide an anti-friction bearing having a solid lubricant bonded on the rubbing and rolling surfaces of said components,

3. A method lubricating an anti-friction bearing as claimed in claim 2 wherein said unassembled components of said bearing are coated by spraying.

4. A method of lubricating an anti-friction bearing as claimed in claim 2 wherein said coated components of said bearing are heated by baking.

5. A method of lubricating an anti-friction bearing as claimed in claim 4 wherein said coated components of said bearing are baked for one hour at a temperature of 300 F.

6. A method of lubricating an anti-iction bearing as claimed in claim 2 wherein saidsolid comminuted lubricant is comprised of a mixture of graphite and molybdenum disulphide.

7. A method of lubricating an anti-friction bearing as claimed in claim 2 wherein said comminuted solid lubricant is comprised of graphite.

8. A` method of lubricating an anti-friction bearing as claimed in claim 2 wherein said comminuted solid lubricant is comprised of molybdenum disulphide.

9. A method of lubricating an anti-friction bearing as claimed in claim 2 wherein said unassembled components of said bearing are coated by dipping.

. 10. A method of lubricating an anti-friction bearing as claimed in claim 2 wherein said unassembled bearing components are coated by brushing.

11. A method of lubricating an anti-friction bearing the components of which are unassembled and include inner race means having a raceway therein, outer race means having a raceway therein, rolling means associated with said inner and outer race means and retainer means associated with said rolling means, comprising the steps of coating said inner and outer race means and said retainer means with a solid comm-inuted lubricant suspended in a thermosetting resin, heating said coated components at a predetermined temperature for a predetermined time to harden said thermosetting resin and thereby bond said comminuted lubricant to said coated components, and assembling the components of said bearing into an operative unit to thereby provide an antifriction bearing having a solid lubricant bonded on the friction surfaces of said inner and outer race means and said retainer means.

12. A method of lubricating an anti-friction bearing as claimed in claim 1l further including the step of drying said coated components in air for a predeterminedtime prior to heating said coated components.

13. A method of lubricating an anti-friction bearing as claimed in claim 12 further including the step of cleaning said inner and outer race means and said retainer means to remove contaminating foreign matter therefrom prior to coating said inner and outer race means and said retainer means.

14. A method of lubricating .an anti-friction bearing the components of which are unassembled and include inner race means having a raceway therein, outer race' means having a raceway therein, rolling means adapted to be received within said raceways within said inner and outer race means and retainer means Iassociated with said rolling means comprising the steps of coating the unassembled components of said bearing with a composite mixture of a solid comminuted lubricant suspended in a bonding agent and thinned with .a solvent to coating consistency to provide a substantially uniform coating on said components having a predetermined thickness, airdrying the coated components of said bearing for a predetermined time at a predetermined temperature to effect the slow evaporation of the rsolvent in said coating to thereby insure the formation of a smooth external surface on said coating, baking said air-dried components of said bearing for a predetermined time at a predetermined temperature to effect a quick setting of said bonding agent and thereby rigidly bond said solid comminuted lubricant to the surfaces lof said bearing components, and assembling said components of said bearing into an operative unit to thereby provide an anti-friction bearing having a comminuted lubricant bonded to the rubbing and rolling surfaces thereof.

15. A method of lubricating an anti-friction bearing as claimed in claim 14 wherein said solid comminuted lubricant is comprised of molybdenum disulphide and graphite having -a particle size not greater than seven microns and wherein said composite mixture of said solid comminuted lubricant, said bonding agent and said solvent is comprised of the following constitutents in percentages by weight: molybdenum disulphide 18, graphite 2, phenolic resin l2 and organic solvent 68. l

16. A method of lubricating an anti-friction bearing the components of which lare unassembled and include inner race means having a raceway therein, outer race means having a raceway therein, rolling means adapted to be received within said raceways within said inner and outer race means and retainer means associated with said rolling means comprising the steps of coating said inner and outer race means and'said retainer means of said bearing with a composite mixture of a solid comminuted lubricant suspended in a bonding agent and thinned with a solvent to coating consistency to provide a substantially uniform coating on said inner and outer race means and said retainer means having a predetermined thickness, air-drying said coated inner and outer race means and retainer means for a predetermined time at la predetermined temperature to eifect the slow evaporation of the solvent in said coating to thereby-insure the formation of a smooth external surface on said coating, baking said air-dried inner and outer race means and' retainer means for a pre determined time at a predetermined temperature to effect a quick setting of said bonding agent and thereby rigidly bond said solid comminuted lubricant to the surfaces of said inner and outer race means and retainer means, and assembling said components of said bearing into an operative unit to thereby provide an anti-friction. bearing having a comminuted lubricant bonded to the rubbing and rolling surfaces of said inner and outer race means and said retainer means.

17. A method of lubricating an anti-friction bearing as claimed in claim 16 wherein said solid comminuted lubricant is comprised of molybdenum disulphide and graphite having a particle size not greater than seven microns and wherein said composite mixture of said solid comminuted lubricant, said bonding agent and said solvent is comprised of the following constituents in percentages by weight: molybdenum disulphide 18, graphite 2, phenolic resin 12 and organic solvent 68.

18. A method of lubricating an anti-friction bearing the components of which are unassembled and include inner race means having a raceway therein, outer race means having a raceway therein, rolling means adapted to be received within said raceways within said inner and outer race means and retainer means associated with said rolling means comprising the steps of coating said retainer means and said raceways in said inner and outer race means with a composite mixture of a solid comminuted lubricant suspended in a bonding agent and thinned with a solvent to coating consistency to provide a substantially uniform coating on said retainer means and said raceways Within said inner and outer race means having la predetermined thickness, air-drying the coated retainer means and the coated raceways within said inner and outer race means for a predetermined time lat a predetermined temperature to effect the slow evaporation of the solvent in said coating to thereby insure the formation of a smooth external surface on said coating, baking said air-dried retainer means and said air-dried raceways within said inner and outer race means 4for Ia predetermined time at a predetermined temperature to eiect a quick setting of said bonding agent and thereby rigidly bond said solid comminuted lubricant to the surfaces of said retainer means and said raceways Within said inner and outer race means, and assembling said components of said bearing into an operative unit to thereby provide an anti-friction bearing having a comminuted lubricant bonded to the rubbing and rolling surfaces of said retainer means and said raceways Within said inner and outer race means.

19. A method of lubricating an anti-fricton bearing as claimed in claim 18 further including the step of masking said inner and outer race means to cover all surfaces thereon other than said raceways prior to coating said retainer means and said racefways.

20. A method of lubricating an anti-friction bearing as claimed in claim 18 wherein said solid comminuted lubricant is comprised of molybdenum disulphide and graphite having a particle size not greater than seven microns and wherein said composite mixture of said solid comminuted lubricant, said bonding agent and said solvent is comprised of the following constituents in percentages by Weight: molybdenum disulphide 18, graphite 2, phenolic resin 12 and organic solvent 68.

12 References Cited in the tile of this patent UNITED STATES PATENTS A V2,078,456 Pew A Apr. 27, 1937 2,280,886v Brace Apr. 28, 1942 2,397,626 Shriver Apr. 2, 1946 2,675,276 Daugherty Apr. 13, 1954 2,685,543 Sindeband Aug. 3, 1954 2,691,814 Tait Oct. 14, 1954' 2,697,645 Mitchell Dec. 21, 1954 2,720,119 Sherman Oct. 11, 1955 FOREIGN PATENTS 657,080 Great Britain Sept. 12, 1951 695,195 Great Britain Aug. 5, 1953 731,348 Great Britain Sept. 8, 1955 757,582 Great Britain Sept. 19, 1956 OTHER REFERENCES Nylon Parts for Ball Bearings, published in Product Engineering, February 1952, pp. 119-123.

Nylon-Clad, published in Product Engineering, Mar. 3, 1958, pp. 52-54. 

